50 kilometers is the equivalent of 31.07 miles. There are 1.61 kilometers in one mile. Kilometers are used in most of the world as the standard unit of measurement for running races and traveling, but in the United States, miles are used instead of kilometers.
A kilometer is a unit of measurement in the metric system. Other units of measurements include meters and centimeters. One meter is the equivalent of about 3 feet. Another unit of measurement in the metric system is Celsius, which measures temperature. There are only three countries in the world that don't use the metric system: the United States, Burma and Liberia.